FN04Mo在七种典型大气环境下的力学性能变化规律及腐蚀机理

Mechanical Properties and Corrosion Mechanism of the FN04Mo on 7 Kinds of Typical Atmospheric Environment

本工作通过金属注塑成型方法制备了FN04Mo样品,并采用电液伺服试验机、X射线衍射分析、扫描电子显微镜、能谱分析仪等对FN04Mo在万宁站、漠河站、敦煌站、拉萨站、江津站、西双版纳站、永兴站七种典型大气环境下的力学性能规律和腐蚀机理进行了研究。研究结果表明,FN04Mo腐蚀初期(1~3个月)力学性能变化呈现明显的下降趋势,试验至3~18个月后其力学性能基本保持稳定。FN04Mo在七种典型大气暴露试验1年后,样品表面均布满腐蚀产物,表面腐蚀形态为点蚀。FN04Mo在富含Cl~-海洋大气环境(万宁和永兴)和富含SO_(2)工业大气环境(江津)下腐蚀最严重。样品在江津暴露1年的腐蚀产物为α-FeOOH、γ-FeOOH以及Fe_(3)O_(4),在永兴暴露9个月的腐蚀产物为β-FeOOH、γ-FeOOH、Fe_(3)O_(4)和FeOCl。侵蚀性强Cl~-和极性强SO_(2)两种大气污染物在大气环境下加剧了FN04Mo基体腐蚀,大气暴露后的FN04Mo样品因腐蚀产物的形成、分层脱落等现象,造成其有效承载面积减小,使其力学性能发生了显著变化。

In this paper,FN04Mo was prepared by metal injection molding.The mechanical properties and corrosion mechanisms of FN04Mo under se-ven typical atmospheric conditions at Wanning Station,Mohe Station,Dunhuang Station,Lasa Station,Jiangjin Station,Xishuangbanna Station,and Yongxing Station were investigated using electro-hydraulic servo tester,X-ray diffraction analysis,scanning electron microscopy,and energy spectrum analyzer.The results showed that mechanical properties of FN04Mo at the initial stage of corrosion(1—3 months)appeared a significant decreasing trend and remained stable after 3—18 months.After 1 year exposure test in the seven typical atmospheres,the surface of FN04Mo was covered with corrosion products and the surface corrosion pattern is pitting.The SO_(2)-rich industrial atmosphere(Jiangjin)is the most corrosive.The corrosion products of the samples exposed for 1 year in Jiangjin areα-FeOOH、γ-FeOOH and Fe_(3)O_(4),while the corrosion products of the samples exposed for 9 months in Yongxing areβ-FeOOH、γ-FeOOH、Fe_(3)O_(4)and FeOCl.The two atmospheric pollutants,the aggressive Cl-and polar SO_(2),aggravated the corrosion of the FN04Mo matrix in the atmospheric environment.The formation of corrosion pro-ducts and delamination of the FN04Mo sample after atmospheric exposure reduced its effective bearing area and led to significant changes in its mechanical properties.